1. Field of the Invention
This invention pertains to a method and apparatus for treating a condition of an upper airway of a patient. More particularly, this invention is directed to such a method and apparatus including an implant to improve patency of the airway.
2. Description of the Prior Art
Upper airway conditions such as obstructive sleep apnea (“OSA”) and snoring have received a great deal of attention. These conditions have recognized sociological and health implications for both the patient and the patient's bed partner.
Numerous attempts have been made towards treating OSA and snoring. These include placing implants in either the tissue of the soft palate or the pharyngeal airway as disclosed in commonly assigned U.S. Pat. No. 6,250,307 to Conrad et al. dated Jun. 26, 2003, U.S. Pat. No. 6,523,542 to Metzger et al. dated Feb. 25, 2003 and U.S. Pat. No. 6,431,174 to Knudson et al. dated Aug. 13, 2002. Further, U.S. Pat. No. 6,601,584 to Knudson et al. dated Aug. 5, 2003 teaches a contracting implant for placement in the soft palate of the patient.
In the '584 patent, an embodiment of the contracting implant includes two tissue attachment ends (for example ends 102b in FIGS. 46 and 47) which are maintained in a space-apart, stretched relation by a bio-resorbable member 102c which surrounds an internal spring or resilient member 102a. After implantation, tissue grows into the attachment ends 102b. The bioresorbable member 102c is selected to resorb after the tissue in-growth permitting the resilient member 102a to contract drawing ends 102b together as illustrated in FIG. 47 of the '584 patent (incorporated herein by reference). Tissue contraction is believed to be desirable in that the tissue contraction results in a debulking of the tissue and movement of tissue away from opposing tissue surfaces in the pharyngeal upper airway.
Another prior art technique for treating OSA or snoring is disclosed in U.S. Pat. No. 5,988,171 to Sohn et al. dated Nov. 23, 1999. In the '171 patent, a cord (e.g., a suture material) (element 32 in FIG. 6 of the '171 patent) is placed surrounding a base of the tongue and secured to the jaw by reason at an attachment member (element 20 in FIG. 6 of the '171 patent). In the method of the '171 patent, the member 32 can be shortened to draw the base of the tongue toward the jaw and thereby move the tissue of the base of the tongue away from the opposing tissue of the pharyngeal airway. However, this procedure is often uncomfortable. This procedure, referred to as tongue suspension, is also described in Miller et al., “Role of the tongue base suspension suture with The Repose System bone screw in the multilevel surgical management of obstructive sleep apnea”, Otolaryngol. Head Neck Surg., Vol. 126, pp. 392–398 (2002).
Two tongue-based surgeries are compared in Thomas et al., “Preliminary Finding from a Prospective, Randomized Trial of Two Tongue-Based Surgeries for Sleep Disordered Breathing”, Otolaryngology-Head and Neck Surg., Vol. 129, No. 5, pp. 539–546 (2003). This article compares tongue suspension (as described above) to tongue advancement (mandibular osteotomy).
Another technique for debulking tissue includes applying radio frequency ablation to either the tongue base or of the soft palate to debulk the tissue of the tongue or palate, respectively. This technique is illustrated in U.S. Pat. No. 5,843,021 to Edwards et al. dated Dec. 1, 1998. RF tongue base reduction procedures are described in Powell et al., “Radiofrequency tongue base reduction in sleep-disordered breathing: A pilot study”, Otolaryngol. Head Neck Surg., Vol. 120, pp. 656–664 (1999) and Powell et al., “Radiofrequency Volumetric Reduction of the Tongue—A Porcine Pilot Study for the Treatment of Obstructive Sleep Apnea Syndrome”, Chest, Vol. 111, pp. 1348–1355 (1997).
A surgical hyoid expansion to treat OSA is disclosed in U.S. Pat. No. 6,161,541 to Woodson dated Dec. 19, 2000. Other tongue treatments for OSA include stimulation of the hypoglossal nerve. This procedure is described in Eisle et al., “Direct Hypoglossal Nerve Stimulation in Obstructive Sleep Apnea”, Arch. Otolaryngol. Head Neck Surg., Vol. 123, pp. 57–61 (1997).